Automatic firearm



April 14, 1931.

J. E. BRowNlNG AUTOMATIC FIIREARM original Filed March 19. 1928 4 Sheets-Sheet i H! W@ .f

INI

April 14, 1931. J. E. BRowNlNG AUTOMATIC FIREARM Original Filed March -19. 1928 4 Sheets-Sheet 2 sli...

.m 1W/my. M... e n f y Nm, Taz. Q

2 3V V W n WH l ...m .009 e.. mw y 1 u, y m .M ...SL r n f ff D m m 4m G, M M, N M 1 M m .m W m m m m M T d m i E M F l w m n@ hb nm o .wm @Uhr No @QWEHIJ www NN, www .S QMR @wk Q w M, m D.. .A mlwnnnnmm nnmlmvmmm April 14, A1931. J. E. BRowNlNG AUTOMATIC FIREARM Original Filed March 19, 1928 4 Sheets-Sheet 4 \\\\\\\\\|`M MWI v l VVMN\ l ow wm NiMH/755mm?? 4tween the lbreech bolt and UNITED STATES PATENT OFFICEA JONATHAN EDMUN BROWNING, OF OGDEN, UTAH, ASSIGNOR TO J. E. BROWNIN G- COM- l PANY, OF OGDEN, UTAH, A CORPORATION 0F UTAH AUTOMATIC FIREARM Application filed March 19, 1928, Serial The invention is applicable to a shoulder arm of rifie caliber and I have shown such a firearm so constructed as to require the manual operation of the trigger to effect the firing of each shot. In regard to this latter feature, however, -I do not necessarily limit myself yand as concerns some of its phases the invention is applicab-le to firearms adapted for full automatic or volley firing.

The invention lrelates particularly to a irearmof the class wherein the barrel and barrel extension and also the breech slide or bolt move rearward upon recoil to a limited extent and wherein the breech bolt is then permitted to move rearward separately from and to a greater extent than the barrel and barrel extension, being returned to its forward locked position automatically. The separate rearward movement of the breech bolt effects the extraction and ejection of the cartridge shell, eifectsthe cocking of the firing mechanism and effects the transfer of a cartridge from the magazine to the firing chamber.

One of the objects of the present invention is to provide a strong and ositive lock bearrel extension v which lock is adapted to be easily released by a movement of the breech bolt transversely or diagonally with respect to the direction of rearward movement of the barrel and barrel extension.

- A further object of the invention is to provide a common means or accelerator, which serves not only to effect the unlocking of the breech bolt from the barrel extension but also serves to accelerate the rearward movement of the holt.

A still further object of the invention is to provide an improved locking means for preventing movement of the barrel extension to its extreme forward position while the breech bolt is unlocked therefrom.

Another object of the invention is to provide an improved safety device for the ire arm.

Still another object of the invention is to provide an improved means associated with the magazinefor engaging the breechbolt to hold it in its rearward open position after No. 262,818. Renewed October 1, 1980.

the firing of the last cartridge in the magazine.

Further objects of the invention will be apparent from the following yspecification and claims. y

In the accompanyin drawings I have shown the embodiment o the invention which I now deem preferable but it will be under Fig. 1 is a right side view of ya firearm embodying the invention.

Fig. 2 is an enlarged fragmentary longitudinal sectional vview taken from the right.

Fig. 3 is a fragmentary rear view on'the same scale as Fig. 2.

Fig. 4 is a transverse vertical sectional view taken along the line of F ig.V 2:

Figs. 5 and 6 are views similar to Fig. 2 but showing the parts in different relative positions.

Fig. `7 is a detail perspective view of the barrel stop lever.

Figs. 8, 9, 10 and 11 are fragmenta. longitudinal sectional views showing d1 erent positions of the barrel stop lever and of the parts with which the said lever directly cooperates.

Figs. 12, 13, 14 and 15 are top, right side,

bottom and front end views respectively showing the receiver and a part of the barrel jacket.

Fig. 16 is a transverse sectional view taken along the line 16-16 of Fig. 13.

Figs. 17, 18 and 19 are top, right side and rear end views showing the barrel extension and a part of the barrel. c

Figs. 20, 21, 22 and 23 are right side, b ottom, rear end and front end views showing the breech cover.

Fig. 24 is a detail pers ective view of the locking pin for the breec cover.

Figs. 25, 26 and 27 are left side, bottom and Irear end views of the safety lever and the operating button therefor. f

Figs. 28, 29, 30 and 31 are right side, front,

Yleft side and rear views of the accelerator.

tional view showing the tiring mechanism and immediately associated parts.

Fig. 38 is a side view of the ring pin.

Figs. 39, 40 and 41 are right side, bottom and rear end views showing the firing pin extension.

Figs. 42 and 43 are right side and bottom views of the scar.

Figs. 44 and 45 are top and right side views of the cocking lever.

Figs. 46 and 47 are top and right side lviews of the trigger plate and associated parts.

Figs. 48 and 49 are top and right side views of the trigger and associated parts.

Fig. 50 is a perspective view of a detachable guard or cover.

Figs. 51, 52 and 53 are top right side and rear views of the magazine partition and associated parts.

Figs. 54, 55 and 56 are top, right side and rear views of the magazine.

Figs. 57 and 58 are top and right side views of the magazine latch.

Fig. 59 is a perspective view of the ejector.

Fig. 60 is a fragmentary horizontal secl tional view showing the cooperative relationship between the ejector and the breech bolt. In the drawings Fig. 1 is a right side view of the gun as a whole, the receiver being shown at 1, the barrel at2, the breech cover at 3, the stock at 4, the barrel cover at 5, and the barrel jacket at 6. The jacket may. be provided with vent holes 6, 6a (See Fig. 2) registering with similar holes in the stock and barrel cover for cooling the gun. The stock and barrel cover are connected by means of rear and forward bands 7 and 8. The trigger is shown at 9, the trigger guard at 10, and the magazine at 11. Sights are shown at 12 and 13, but the invention does not relate to the sights and sights of other types may be substituted for those shown.

The relationship between the receiver 1 and'certain other parts of the gun is shown in Figs. 2 to 6 and the structural details of the receiver are shown in Figs. 12 to 16. The receiver, 1 has a main substantially tubular portion 14 which is open at the rear and front ends and which is adapted to be lconnected at its front end with the rear end of the barrel jacket 6, a threaded connection being shown. The receiver 1 is provided with parallel longitudinal side walls 15, 15 which are adapted to receive between them the lower part of the barrel extension and to serve as guides controlling the longitudinal movement thereof. At the rear the receiver is connected with the reaction spring tube 16 which ejection of empty shells therethrough.

The barrel 2 and the barrel extension 20 are shown in operative relation with other. $0 parts in Figs. 2 to 6 and their details of conl struction are shown in Figs. 17 to 19. The barrel and the bar rel extension are suitably connected together as by threading and the barrel is provided at the rear with the usual cartridge chamber 21. The barrel extension is formed to receive the breech bolt as will presently appear and it is further formed at the bottom with guide portions 22, 22 adapted to it between and be guided by the side walls 15, 15 of the receiver. The relationship between the barrel extension and the receiver is clearly shown in Fig. 4. Upon assembly the barrel and barrel extension are inserted from the rear, the barrel extension being guided between the walls 15, 15. When the mechanism is completely assembled the barrel and barrel extension have only a limited movement with respect to the receiver. The barrel extension is provided with a bottom 10u opening which has a relatively wide lower portion 23 adapted to receive the upper part of the magazine 11 as willv presently appear and having -a narrower upper portion 24 v adapted to permit the passage of cartridges 105 therethrough. The portions of the barrel'eX- tension at the two sides of the opening 24 con stitute parallel spaced guide rails with which the breech bolt engages in the manner to be presently described. Near the rear the wider llo portion of the opening extends entirely through as shown at 25, thus forming .a forward facing shoulder 26. The barrel extension has an opening 27 in the sidethereof which normally registers with the opening 19 116 in the receiver and is adapted for the ejection of empty cartridges. A

Fig. 2 shows the breech bolt28 in its normal relationship with the other parts of the gun, and this figure also shows some of the de- 120 tails of the said breech bolt. Other details will be described later. The main body of the breech bolt 28 is preferably of unitary construction, having all of its parts rigidly maintained in fixed relation to each other. The lli breech bolt 28 is heldin its forward position by means of a strut 29 pivotally connected with the rear portion of the said bolt at 30. The rear end of the strut 29 engages a plunger 31 which is slidable inthe reaction spring l tube 16. The reaction spring 32 inthe said fr is effected by causing the breech bolt or'at least the rear part thereof to move transversetension 47 at the `rear of the lever extends,

ly or 'diagonally with respect to the direction of movement of the barrel extension. Preferably only the rear end of the bolt is thus' moved diagonally, the front end moving directly rearward and the bolt being thus given an angular or tilting movement about a transverse axis near the front end thereof.

Figs. 2 and 3 show the breech cover 3 in its operative relationship with the other parts and details of constructon of the cover are shown in Figs. to 23. It will be observed4 that in assembly the front part of the breech cover is hooked under a portion of the receiver at the rear as indicated at 34 and the side walls of the cover .extend down between the side walls 15, 15' of the receiver asclearly shown in Fig. 3. The cover is held in place by means of a transverse pin 35 which extends through holes 36 in the cover and through transverse holes 37 in the said side walls 15, 15. The pin 35 is shown in detail in Fig. 24. The pin 35 carries a locking lug 38 which is passed through a notch 39 in one of the holes 37, the pin thenbeing turned by means of the attached lever so as to bring the locking lug 38 in engagement with the inner face of the corresponding wall 15.'`

The breech cover 3 has at the front a downward projection 41 which is adapted to engage an upward projection 42 on the breech bolt as shown in Fig. 2, the said projections being provided respectively with inclined cam surfaces 43 and 44. When the two pro jections are in engagement as s hown the breech bolt and barrel extension are held in their described locked relationship, it being impossible for the lug 33 to become disengaged from the shoulder 26.

As shown in Fig. 2 the various parts of the gun are in the normal position ready for firing, which, however, is impossible by reason of the position of the safety lever 45. This safety lever is shown in detail in Figs. 25, 26 and 27. The said safety lever 45 is pivotally mounted at 46 on a stud carried by the receiver at the left side and an upward exthrough a slot 48 in the receiver to an exposed position at the left hand side of the cover 3, the. said cover being recessed at 49 to provide space for the said extension. The safety lever carries a detachable button `50 which` facilitates manual movement of the lever. At the forward end of the lever 45 is an upward extension 51 which extends through -a slot 51" in the receiver and is adapted to project into the path of movement of the rear lend of the breech bolt as clearly shown in Fig. 2. The safety lever 45is further provided with a downward extension 52 which serves to lock the trigger,-as will be hereinafter explained, when the lever is in the position shown in Fig.r2. Thesafety llever can be manually moved in the clockwise direction, as viewed in Fig. 2, to its firing posit-ion wherein the breech bolt and trigger are free for movement. (See Fig. 37.) To yieldably hold the lever in either of its `described positions there is provided a detent4 pin 53 on the receiver adapted to enter either ofl two notches 54, 54 in the lever.

As already stated the breech bolt and barrel extension are directly locked together when ,in the -'ring position. ,When firing occurs the barrel and barrel extension' move rearward under the force of the' recoil, and the breech bolt, by reason ofthe described locked relationship, initially moves rectilinearly in unison with them. As already stated the f breech block is unlocked vfrom the barrel extension by moving at least a part thereof away from itsinitial path of rectilinear movement. When the engagement betweenthe breech block and the barrel extension is byy means of' a downward projecting lug such as 3,3, the breech bolt, or at least a part thereof, is moved transversely or diagonally, upward and rearward until the lug 33 is-disengaged" from the Abarrel extension. After disengagement the breech bolt continues to move rearward and the motion of the barrel extension and barrel is stopped. The means for effecting the transverse or diagonal unlocking movement of the breech bolt may be varied, but I prefer to provide a single breech bolt operating means serving upon recoil iirst tov unlock the breech bolt as described and then to move it rearward separately from the barrel and barrel extension. By preference I used for this purpose the means shown in the drawings, which means I will now describe.

Mounted in the rear part of the opening 18 of the receiver is a member 55 which serves as the breech bolt operating means and I will refer to as anaccelerator, this member being shown in detail in Figs. 28, 29, 30 and 31. The accelerator is pivotally mounted on a transverse pin 56 which extends into bearing apertures 57, 57 in the receiver. The main body portion of the accelerator is curved upward and rearward having a convex forward facing surface 58 whichis adapted to cooper atively engage the fiat rearward facing surface 59 of the barrel extension. By reason of the engagement of the accelerator with the surface 59 of the barrel extension the said accelerator is moved `in the counter-clockwise direction until the upper end thereof engages the breech bolt at 60. The timing is such that when the accelerator engages the breech bolt as stated the breech bolt has moved rearward sufficiently to permit the flat horizontal surfaces of the proJections 41 and 42 to disengage each other, the rear part of the breech bolt then being free to move diagonally upward along a path determined by the engagement of the cam surfaces 43 and 44. Continued pressure exerted by the rearward moving barrel extension on the accelerator causes the accelerator to force the rear part of the breech bolt upward and rearward to the position shown in Fig. inrwhich position the lug 33 is about to disengage the shoulder 26. lt will be observed that the front part of the breech boltl does not partake of the diagonal movement but moves in a substantially straight path. The rearward pressure of the barrel extension upon the accelerator continues and the accelerator now serves to move f the breech bolt rapidly rearward, imparting to it a velocity which enables it to move in opposition to the spring 32 approximately to the position shown in Fig. 6, being guided in part by the inner surface of the cover. It will be seen that the accelerator serves to transfer the energy of the moving barrel and barrel extension ,to the said breech bolt, the result being that the movement of the barrel and barrel extension is gradually retarded and finally stopped while the absorbed energy is imparted to the breech bolt to throw it backward to the position of recoil.

During the separate rearward movement of the breech bolt the rear part vthereof engages and is guided by ledgesl, al formed on the receiver. These ledges are spaced :lpart and the strut 29 is positioned between As clearl indicated in Fig. 6, the lower surface of t e lug 33 of the breech bolt serves as an abutment which remains vin engagement with the accelerator during the separate rearward and return movements of the breech bolt. Thus the accelerator is held in its reariost dposition as indicated. It will be observe that the lower surface of the lug 33 is so inclinedwith respect to the -main bod of the bolt that uponv an lar movement of the bolt it assumes a position parallel with the direction of the separate rearward movement. Thus, the accelerator is held immovable during such movement.

There is provided a sto 61 on the barrel extension w ich is engage by the accelerator when the extreme position is reached, the

said accelerator being recessed at 62 to receive the said stop. The engagement of the stop with the accelerator prevents further rotative movement of the latter and at the same time a shoulder 63 on the accelerator engages the bottom of the barrel extension. It will be obvious that the stop 61 serves to holdpthe barrel extension in its rearmost position until suchv time as the breech bolt returns forward far enough to release the accelerator.

As soon as the breech bolt reaches its rearmost position as shown in Fig. 6 it is immediately returned in the forward direction by reason of the action of the spring 32 and associated parts. As the breech bolt moves forward the lug 33 releases the accelerator and immediately thereafter the forward A'zol facing surface at re-engages the accelerator and causes it to move in the clockwise direction'to the position shown in Fig. 5. As the accelerator moves in the clockwise direction the barrel and barrel extension move forward in unison with the breech bolt but ata slower speed. As soon as the position shown in Fig. 5 is reached the cam surfaces 43 anda-4 engage each other, the result being that as the breech 'bolt continues to move forward it is returned to its locked relationship with the barrel extension as shown in Fig. 2. The final movement `of the breech bolt in the forward direction carries the barrel and barrel extension-with it in locked relationship, thus complletel restoring the parts to the relations ip s own in Fig. 1. Preferably in order to positively ensure the return of `the accelerator to the position ,shown in Fig. 2 I provide a lug 64 on the barrel extension this lug engaging a tooth 65 on the accelerator to positively move the accelerator to its extreme vforwardposition. f v

To assist in iding the Vbreech bolt 28 'and in securing it rmly in the firing position I have provided a guide -rib 28' at the forward end of the bolt which enters and lits a groove 28b in the barrel extension. To further assist in guiding'the breech bolt I provide a guide rib 22a on the barrel extension which enters and lits a groove 22 in the breech bolt.

When the breech bolt is in its forward posi-- tion the rib 28 and the groove 28b are effec'- tive and in an intermediate osition as shown in Fig. -5 the' rib422 and t e groove 22" are effective.

The strut 29 may be utilized to assist in absorbing the energy of recoil of the breech bolt 28. The said strut may be resilient and ioo so designed as to frictionally engage the tube n l' 16 as shown at 29a in Fig. 6. The bolt is uided by the ledges y15?, 15v for movement m a straight lineand as -it reaches its rearmost position there is a tendency to flex the strut. This tlexin tendency considerably increases the friction at 16, and thus the strutv acts as a brake to 'assist the -spring 32 in stopping the movement of the bolt.

During counter-recoil movement when the parts approach the position shown in Fig. 5,;

it is desirable to provide means to prevent movement of the barrel extension forward to a position in which it could not be reengaged by the breech bolt. I therefore provide a stop mechanism to prevent movement of the barrel extension to its eXtreme forward position, this mechanism beingshown in Figs. 7 to 11. Within the receiver near the right side thereof there is provided a locking lever 66 having a trunnion 67 which extends into a hole 68 in the receiver. The locking lever 66 carries a rib 69 which, when the lever is in operative position, projects into a slot 70 in the receiver and revents the trunnion 67 from being with rawn from the hole 68. The locking lever 66 has a tooth 71 which is adapted to hook under. and en age a shoulder 72 on the barrel extension an the lever further has an upper cam surface 73. A spring 74 carried by the receiver tends to move th lever in the upward direction.

When the parts are in the position shown in Fig. 8, which is the same position as that shown in Fig. 2,-the tooth 71 of the locking lever merely engages the flat bottom surface of the barrel extension, the said barrel eX- tension being thus free to move. Carried by the breech bolt 28 is a lug 75 adapted to engage the cam surface 73 of the locking lever.\ When the parts are moved rearward to the position shown in Fig. 9, which is the same position as shown in Fig. 5, the lug 75 engages the cam surface 73 to force the lever 66 downward, thisdownward movement being an incidental one of no functional importance. When the breech bolt moves rearward from the position shown in Fig. 9 to the positionshown in Fig. 10, which latter position is the same as that shown in Fig. 6, the lu 75 is entirely free fromv engagement wit the upper cam surface 73 of the lever 66. However, when-the parts, are in this position the said cam surface 73 is engaged by a cam surface 76 on the barrel eX- tension and is therefore held downward in opposition tothe spring 74. However, if the barrel and barrel extension move forward independently of the breech bolt toward the position shown in Fig. 11, the cam surface 6 is disengaged from the locking lever and the sprin causing th 74 :forces the lever upward, thus e tooth 71 thereof to engage the shoulder 72 of the barrel extension and prevent continued forward movement of the said barrel extension beyond the position shown in Fig. 11.' As the breech bolt continues to move forward the said lug 75 again engages the 'lever 66. The parts are so timed that when the front end of the breech bolt is engaged with the barrel and when the lug 33 is entered in front of the `shoulder 26, the lug 75 moves the lever 66 downward far enough to `disengage the tooth 71 from the shoulder 72 and thus releasethe barrel eX- tension for forward movementv with the breech bolt to the position shown in Fig. 8.

Further details of the breech bolt are shown in Figs. 32 to 36 which figures show not only the breech bolt but certain partsdirectly associated therewith. The breech bolt carries at the right side a handle 77- which maybe used to manually operate the mechanism of the gun. YThis handle extends laterally throughthe openings 27 and 19 in the barrel extension and receiver respectively. Adjacent the forward end of the breech bolt and at the right side thereof there is provided a pivoted extractor 78 which is normally pressed into its operative position by means of a spring 79. The breech bolt has a central opening 80 therein adapted to receive the firing pin and firing pin extension,

there being a smaller opening 81 at the front through which the firing pin proper extends to engage the cartridge. A vertical longitudinal sectional view of the breech bolt is shown in Fig. 37 which figure also shows various other parts whichv are lclosely associated with the breech bolt. The firing in 82 is shown in detail in. Fig. 39 and the ring pin extension 83 is shown in detail in Figs. 39 to 41. The firing pin extension 83 is provided with a central opening 84 for receiving the spring 85. The firing pin 82 is threaded into the front part of the opening .84. The ring pin extension has a trans verse slot 86 through which extends a screw pin 87 located in vertical holes 88 in the breech bolt. This pin 87 serves as a rear abutment for the spring 85. The spring reacting a ainst the pin 87 tends to move the entire rin pin and extension forward to `firing posit1on.l The firing pin and firing in extension are held in their rearward `coc ed position as shownl in Fig. 37 by means of a sear 88 which engages a shoulder 89 at the rear of the rin pin extension. The Sear isv shown in detal in Figs. 42 and'43. The sear 88 is pivotally mounted on a` transverse pin 90 which is lo-4 cated in transverse holes 91 in the breech bolt. A spring 92 supported on a transverse pin 93 serves to press the sear upward. The sear is provided with a downward hook eX- tension 94 adapted to be engaged by the trig` ger lever as will' presently be described.

The cooking lever 95 is shown in detail in Figs. 44 and 45 and is shown in its operative relation with otherparts in Figs. 37, 2, 5 and 6. This lever is pivotally mounted on a transverse pin 96 which is located in transverse holes 97 inthe breech bolt. The lower part 98 of the lever is slotted at 99 for a purpose which will presently appear, and the upper part 100 thereof extends into thebev fore-mentioned slot 86 in the firing pin, being adapted to engage the surface 101 at the rear end of the said slot. When the las mechanism is in the ring position as shown in Figs. 2 and 37 the lower end of the cocking lever is inclined toward the rear being f located between the rear part of the accelerator and the `shoulder 102 of the receiver.Y

The firing pin and extension are in cocked position as shown so that the surface 101 is out of engagement with the cooking lever.

When the firing pin and firing pin extension are released by the sear 88 to edect firing they are forced forward under the action the spring l thus bringing the surface 101 into engagement, or substantially into engagement, with the upper part 100 of the cooking lever. Immediately thereafter the breech bolt is forced rearward by the recoil action as already described, first to the position shownv in Fig. 5 and then to the position shown in Fig. 6. As the breech bolt moves rearward the lower part 98 of the cooking lever is forced against the shoulder 102 on thel receiver and it then travels along the surface 103 onthe receiver as shown in Fig. 6. When the cooking lever reaches the position shown in Fig. 6 the ring pin extension with the iiring pin has been forced rearward .far enough to permit the Sear 88 to engage the shoulder 89 and thus hold the parts in cocked position. As the breech bolt and associatedv parts return forward to the position shown in Figs. 2 and 37 the motion of the cooking lever is reversed, this lever returning toits original position as described. y

The combined triggerl plate and guard with associated parts is shown in Figs. 48 and 47 and the trigger with associated parts is shown in Figs. 48 and 49. The trigger plate 104 has the ard 10 formed as an integral part thereof and the said plate is suitably secured in place, screws 105 and 105a being shown for this purpose. These screws in cooperation with a third screw 105b also serve to hold the stock 4 in place. The plate is of conventional construction and no detailed description is necessary. rIhe trigger 9 is pivotally mounted on the trigger p ate at 106, and projects downward through an aperture 107 in the said plate. The trigger has pivotally connected with it at its forward end a link 108 which is normally pressed in the counter-clockwise direction by Ameans of a spring 109 abutting at its lower end against the trigger plate, the spring being held in place by a pin 109% A shoulder 110 on the trigger limits the movement of the said link. The link 108 extends through the slot 99 in the cooking lever 95 and is provided with a notch 111 which is positioned to receive the end of the extension 94 of the Sear when the breech bolt and the parts carried thereby are in their forward positions as shown in Fig. 37 It will be obvious that with the parts in the positions shown in this Yfigure the trigger when pulled will transmit motion through the link 108 to pull the sear 88 downward and release the firing pin. It will further be apparent that the sear is free to' disengage the link when :the breech bolt and associated parts are 'moved'rearward upon recoil. g

The trigger is provided withA a notch 112 which is adapted to'receive the extension 52 f on the safety lever.when the said lever is in its safe position as shown in Fig. 2. It will be apparent that the safety lever serves not only to lock the breech bolt'as already de-.

scribed but also serves to lock the trigger against movement. When the safety lever is moved to its firing position as shown in Fig.

fectively close the opening in the side of the gun when the parts are in their normal iring positions. The said cover 113 is provided with an opening 11d-therein which is circular at its outer end and which isin the form'of a narrow slot at its inner end. 'Carried by the breech bolt is a stud 115 having a T-head adapted to enter the hole 114 when the cover.

113 is in a. verticalposition with the hole at the top, ,When the cover is turned to its normal horizontal position the head on the stud A 115 lies in the outer circular part of the hole 114 and the cover is locked in position. A projection 113l on the cover enters a slot 113b in the breech .bolt to limit the upward pivotal movement of the cover about the stud 115.

The engagement of the projection 113 in the slot 113b also assists'inleking the cover in place. lt will be understood that the-cover 113 is attached tothe b eech bolt prior to the insertion of 'the latter)1n the barrel exten-A sion. 1

Positioned transversely of the opening 18 in the receiver is a partition 116 shown in detail in Fi 51 to 53. This partition is held in place y means of a transverse pin 117 extending through holes 118 in the receiver.

A screw 119 extending through a hole 120 in the receiver prevents rotative movement about the pin 117.

The magazin 54 to y56. rlhe maga-zine is adapted to enter the receiver at the bottom, being positioned within that part of the space 18 which is in front of the partition 116. The m azine is or may be formed of sheet metal in t e usual way and it is which is presse upward by means of a spring 123. The ma azine is somewhat wider at the rear than at t e front in order to permit cartridges to be positioned therein in staggered relationship as indicated in Fig. 2. Thefollower has an upward projection 122 at 'one side which serves to hold the lowermost carprovided with a follower 122 e 11 is She-wn in dei-,ail in rigs.

tridge toward the oppjositeside of the magazine.

The latch\124 for releasably holdinthe 1gs.

through a holel 126 in the, partition l116 and into a notch 12Linv the'magazine.-` 'Iqhe said latch 124 is further provided with a downward projecting linger piece 128 which extends through a hole 129 in the trigger plate so as to be conveniently accessible at a point immediately in front .of the trigger guard. The latch is provided `with a longitudinal slot 130 which is positioned to receive a sprmg pressed plunger 131 carried by the trigger plate. The trigger 9 and the trigger link 108 also extend into the slot 130 and the rear portion 128'a of the latch extends under the trigger as shown in Fig. 37, being thus held in place and prevented from moving upward. The said spring pressed plunger 131 normally serves to press the latch,l24 forward to its operativeposition to hold the magazine. When it is Ydesired to release the magazine the finger piece 128 is pressed rearward in opposition to the spring pressed plunger 131, thus withdrawing the tooth 125 from the notch 127.

Assuming the parts to be in the position shown in Fig. 2, it will be apparent that, when firing occurs and the barrel, barrel extension and breech bolt move as already de-v scribed, the extractor 78 on the breech bolt will draw the empty shell out of the firing chamber and 'carry 1t rearward to a position oppositethe ejection openings 27 and 19. For ej ecting the shell through the said openings there 1s provided an ejector 132 which vis shown in detail in Fig. A59 and which is shown in operative relation with the breech bolt in Fig. 60. The ejector is mounted in a slot 133 in the barrel extension being pivotally held by means of a vertical pin extending through a hole 134. The breech bolt is provided with a cam surface 135 which engages the tail 136 ofthe ejector to force it in the clockwise direction as the breech bolt nears its rearmost position. When the ejector is thus turned its front end portion lies I in the path of the'em ty shell on the left.

side thereof, the right slde of the shell being engaged by the before mentioned extractor 78. The ejector 132 therefore serves to forcibly tilt the shell laterally, disengaging it from the extractor and forcibly snapping it outward through the ejection openings 27 and 19. j Y

As soon as the breech bolt reaches its rear position as shown in Fig.V 6 a cartridge from the magazine is forced upward bythe follower int`o the path of return movement of the bolt. As the bolt moves forwardthe cartridge is pushed into the firing chamber.

Carried by the partition 116 is a vertically movable slide or stop 137 which is normally held in its lowermost position by means of a spring 138. Av forward extension on the upper end of the s'lideor stop 137 lies adjacent the rear edge of the magazine and in thepath of upward movement of a rear portion 122b ofthe follower 122. After the llast .cartridge has been ired-the'follower 122 occupies its uppermost position as shown in Fig. 6, the portion 122b thereof thus engagward in opposition to the spring 138. The parts are so related Athat 'when the slide reaches its upper position as shown in Fig.

6 it serves as a stop to engage a downward extendlng lug 139 on.| the breech bolt 28.l

Thus the breech bolt is held in its rearmost posltlon as 'shown after the last cartridge has been lired. This serves as a warning to the gunner that the last cartridge has been fired and that theempty magazine should be replaced by a loaded one, and it also facilitates reloading as it avoids the necessity for manually operating the breech bolt to insert the lirst cartridge into the firing chamber. After the loaded magazine has been put in place the slide or stop 137 can be releasedand permitted to return to its inoperative position by simply drawing the 'breech bolt back sli htly to relieve the pressure on the stop. 'Ighen the breechbolt can be released and permitted to move forward in the usual way, carrying with it a cartridge from the newly inserted loaded magazine and insert- 'ing it into the firing chamber.

A suitable means is rovided for holding the cartridges toward'tiie front of the magazine in order to provide sufficient space at the rear for the said forward extension on the slide or stop 137. When the magazine is formed of sheet metal I prefer to locate the seam 140 thereof at the rear and projecting inward from the main rear wall. The details of the seam 140 are shown in Fig. 54 but in the other figures the several thicknesses` of the sheet metal are omitted for the sake of simplicity. It will be observed that the yseam serves as the required .means for holdying the slide or stop 137 and forcing it up- 1. In a firearm of the class described, the

combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable unitary breechV bolt normally in locked engagement with the barrel extension and hav- -ing its parts rigidly maintained4 in fixed relation with-each other, and means operatively dependent on the rearward movement of the barrel extension and breech bolt for causing at least a portion of the said breech bolt to bodily move transversely with respect to the barrel extension so as to eii'ect disengagement of the 4former from the latterand means dependent upon the rearward movement of the barrel-extension for causing additional rearward movement of the bolt separately from A tively to the receiver, a rearward movable unitary breech bolt normally in locked engagement with the barrel extension and having its parts rigidly maintained in lixed relation with each other, means operatively dependent on the rearward movement. of the barrel extension and breech bolt for moving the said breech bolt as an entirety angularly about a transverse axis so as to effect disengagement of the bolt from the barrel extension, and means dependent upon the rearward movement of the barrel extension for causing additional rearward movement of the bolt separately from the barrel extension.

8. In a rearm of the class described, the combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, the said barrel extension including two longitudinally extending parallel spaced guide rails and a transverse' portion connecting the rails at the rear and forming a forward facing shoulder between them, a unitary breech bolt slidably engaging the said rails and having its parts rigidly maintained in fixed relation with each other, theV said breech bolt having a downward projecting rearward facing lug located between the rails and normally engaging the said forward facing shoulderto hold the bolt in fixed relation with the barrel extension, and means operatively dependent on the rearward movement of the barrel extension and breech bolt for moving the said bolt as an entirety angularly upward about a transverse axis at the front thereof so as to eect disengagement of the lug from the, shoulder and thereby permit separate rearward movementl of the bolt.

4. In a firearm of the vclass described, the combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked .engagement with the barrel extension, a member connected with the receiver for pivotal movement about a fixed transverse axis and serving during rearward movement of the barrel extension and breech bolt to engage and bodily move at least a part of the said .breech boltl transversely with respect to the barrel extension so as to effect disengagement of the bolt from the extension and thereby permit separate rearward movement of the bolt.

5. A firearm as set forth in claim 4, wherein the breech bolt is unitary Vand has its parts rigidly maintained in fixedrelation with each other.

6. A firearm as set forth in claim 4, wherein the breech bolt is unitary and has its'parts rigidly maintained in xed relation with each other, and wherein the said breech bolt is angularly moved by the said pivoted member about a transverse axis near its front end.

7. In a firearm of the class described, the combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked engagement with the barrel extension, a member pivotally connected with the receiver for causing at least a portion of the breech bolt to move diagonally-with respect to the direction of movement of the barrel extension to effect disengagement of the formerifrom the llatter, and a cam cooperating with the said pivotally connected member to control the said diagonal movement.

8. ln a firearm ofthe class described, the combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked engagement with the barrel extension, a member pivotally -connected with the receiver for causing at least a portion of the breech bolt to move during recoil diagonally in one direction with respect to the direction of movement of the barrel extension to effect disengagement of the former from the latter, and a -cam carried by the receiver and serving during counterrecoil to move the-said portion of the breech bolt diagonally in the opposite direction to sion.

effect reengagement with the barrel extencombination-of a receiver, a barreland'barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked engagement with the barrel extension, a cover removabl'y connected'with the receiver and partly enclosing the path of movement of the breech bolt, and means including a cam carried by the cover for causing at least a portion of the breech bolt to move during recoil diagonally-in one `direction with respect to the direction of movement of the barrel extension to effect disengagement of the Vformer l from the latter and to move during counterrecoil diagonally in the opposite direction to effect reengagement'.

10. In a firearm of the class described, the

combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech'bolt'normally in locked engage- '5 ment with the barrel extension, a member pivotally connected with the receiver for I causing 'at least a portion of the' breech bolt to move diagonally with respect to the direction of movement of thebarrel extension to effect disengagement of the former from the latter, a cover removably connected with the receiver and artly enclosing Vthe path of movement of t e breech bolt, and a camcarried by the cover and cooperating with the said pivotally connected member to control the said diagonal movement.

11. In a firearm of the class described, the combination of a receiver, a barrel and barrel extension movable upon recoil reary the s'aid bolt rearward separately from the barrel extension.

12. A ,firearm as set forth in claim 11, wherein the breech bolt is unitary and has its parts rigidly `maintained in fixed relation with each other.

13. A rearm as set forth in claim 11, wherein the breech bolt is unitary and has its parts rigidly maintained in fixed relation with each other, and wherein the said breech bolt is angularly moved about a transverse axis near its front end.-

`14. A firearm as set forth in claim 11, wherein thevbreech bolt operating means is a single unitary element.

15., In a firearm of the class described, the

combination of a receiver, a barrel and bar rel extension movable upon recoil rearward relativelyto the recei-ver, a rearward movable breech bolt normallyv in locked engagement with the barrel extension, and an accelerator having engagement with the receiver and with the breech bolt and pivotally y connected to one of them for movement about a transverse axis, the said accelerator being engaged and relatively moved by the barrel extension during recoil movement and thereby serving first to move at least a portion of the breech bolt transversely with respect to the'barrel extension toeffect disengagement of the former from the latter and then to move the said bolt rearward separately from the barrel extension.

f16. In a firearm of the class described, the combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked engagement with the barrel extension, and an accelerator pivoted to the receiver for movement. about a fixedl transverse axis and actuated by the barrel extension during recoil movement, the said accelerator serving upon recoil Afirst v to move at least a portion of the breech bolt ltransversely with respect to the barrel extension to effect disengagement of the former from the latter and then to move the said bolt rearward separately from the barrel extension.

17. A firearm as set forth in claim 16,

wherein the breech boit is unitary and has its parts rigidly maintained in xed relation with each other, and wherein the said breech bolt is angularly moved by the said acceler- Y ator about a transverse axis near its front` end.

18. In a rearm of the class described, the

combination of a receiver, a barrel and barrel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked engagement with the barrel extension, and an accelerator pivoted to the receiver for movement about a fixed transverse axis and having a convex forward facing surface in the path of rearward movement of a rearward facing surface of the barrel extension, the said accelerator serving upon being engaged and actuated by the barrel extension first to move at least a portion of the breech bolt transversely with respect to the barrel extension to effect disengagement of the former from the latter and then to move the said bolt rearward separately from the barrel extension.'

19. A rearmas set forth in .claim 18,`

wherein the accelerator has a tooth additional to the main body portion thereof and wherein the barrel extension has a lug adapted to engage the accelerator tooth to return the accelerator in the forward direction when the barrel extension moves in the first to move at least a portion of the breech e bolt transversel with respect to the barrel extension to e ect disengagement of the former from the latter and then/to move the said bolt rearward separately from the barrel extensionand separately from the' said operating means,- and an abutment on the breech bolt serving during a part of the separate movement thereof to engage the said operating means and thereby hold the 'barrel extenslon in its rearmost position.

21. In a firearm f the class described, th

combination of a receiver, a barrel and barf' rel extension movable upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked engagement with the barrel extension, an accelerator pivoted' tothereceiver for movement about a fixed transverse-axis and actuated by the barrel extension during recoil move-v' ment, the said accelerator' serving upon recoil first to move at least a of the breech bolt transversely with' respect to vthe barrel extension to effect ortion vsition while the accelerator is in its rearmost position. L l

22. A rearm as set forth in claim 21, wherein the breech `bolt has its parts rigidly maintained in fixed relation with each otherV and is angularly movable as an entirety by the accelerator aboutie. transverse axis near the front end, and wherein the abutment means, on the breech bolt engaging'the accelerator has an inclined accelerator engaging surface which upon a ar movement of the bolt assumes a posihon parallel withpthe direction of the separaterearward movement of the bolt. Y

23. ln a rearm oi the class described, the combination of a receiver, a barrel and barrel extension' movable-upon recoil rearward relatively to the receiver, a rearward movable breech bolt normally in locked engagenient with the barrel extension, a breech bolt opera means actuated by the barrel ex,- tension uring recoil movement and serving lirst to move at least a portion of the breech bolt transversely with respect to the barrel extension to eEect disengagement of the former 'om the latter land then to move the said bolt rearward separately from the barrel extension and separately from the said operating means, an abutment on the breech bolt serving during a part of the separate movement thereof to engage the said operating means and thereby hold the barrel extension in its rearmost position and a latch additional to the breech bolt operating means and serving to prevent movement of the barrel extension to its extreme forward osition prior to the return of the breech lt to locked engagement therewith.

2d. lin a iearm of the class described, the combination of a receiver, a barrel and bar- Arel extension movable upon recoil rearward relatively to the receiver, a rearward movablebreech bolt, releasable means normally locking the breech bolt to the barrel extension, means operative upon recoil to unlock the breech bolt from the barrel extension and permit it to move rearward separately thereof, a spring for returning the breech bolt to its normal locked position, a movable latch separateom the said breech bolt lookin means and located at one side of the breec bolt, the said latch serving to` prevent movement of the barrel extension to its extreme' forward position Vwhile the breech bolt is unlocked therefrom, and e' lu projecting latorally from the breech bolt or engaging ,the

incinta;

25. lira firearm ofthe class described, tlie` combination of a receiver, a barrel and barrel extension movable upon recoil rearward rel.

atively to the receiver, a rearward movable breech bolt normally .in locked engagement 'i with the barrel extension, means operative upon recoil to disengage the breech bolt from the barrel extension so as to permit it to move rearward separately therefrom, i.

means operative after disengagement of the bolt from the barrel extension for guiding it as an entirety for rectilinear movement, a so tube connected with the receiver at the rear and positioned at au angle to the direction of bolt movement, a reaction spring in the tube, and a strut pivotally connected with the rectilinearly movable breech bolt and extending intothe tube to be operatively associated with the spring, the said strut by reason `of the angular position of the tube frictionally engaging the tubeV .during recoil to assist in retardingl ther recoil movement of the bolt.- l

26. ln a rearm ci the cl ss described, the

combination of a barrel andbarrel extension f movable rearward upon recoil, a rearwardA movable breech bolt, releasable means normally locking the breech bolt to the barrel extension, a rin actuated ring pin mounted in the reec including a trig er releasing .the riiig pin, means opera le upon recoil for unlockingthe breech bolt from the barrel extension lolt, iiriiig` mechanism o ico to permit it to move rearward independently thereof, and a manuallyl operable safety lever pivoted for movement about a transverse axis and having two arms extending in dierent directions and respectively sc i'v- Y osition ing when the lever isin its safety to prevent rearward movement o rel and barrel extension and to eration of the firing mechanism. l 27. In a firearm of the class described, the

t e barcombination of a barrel and barrel extension movable rearward upon recoil, a rearward movable breech bolt, releasable means normally locking the breech bolt to the'barrel extension, a spring actuated firing Afpin mounted in the breech bolt, firing mechanism including a trigger for releasing the firing prevent cpi pin, means operable upon recoil for unlocking the breech bolt'from the barrel extension thereof, and a manuallyoperable;l safety in dierent directions andi respectively serving when the lever is in its safety position' t0 engage the breech bolt to prevent rearward leo to permit itv to move rearward independently movement of thesaid bolt or'of vthe barrel 'I and barrel and to engage the ger to prevent operation of the firing mechamsm.

28. In a firearm of the class described, the combination of a barrel and barrel extension movable rearward upon recoil, a rearward movable breech bolt, releasable means normally locking the breech bolt to the barrel extension, means operative upon recoil to unlock the breech bolt from the barrel extension VVand permit it to move rearward inl dependently thereof, a spring for returning the breech bolt to its normal locked posi- Y tion, a removable magazine having a follower-for moving cartridgessuccessivel into the path of return movement of the olt, a stop mounted independently of thel magazine and adapted to be engaged by the follower and moved upward into the path of return movement of the bolt after the last cartridge has been removed from the magazine, the said stop thus serving to hold the breech bolt in its rearward position, and means in the magazine at the rearfthereof for holding the cartridges forward and thus vpreventing their engagement with the said stop.`

29. vIn a firearm of the class described, the combination of a barrel and barrel extension movable rearward upon recoil, a rearward movable breech bolt, releasable means nor-1 mally locking the breech bolt to the barrel follower for moving cartri extension, means operative upon recoil to unlock the breech bolt from theba'rrel extension and permit it to move rearward inde-l Apendently thereof, a spring for returning the reech bolt to its normal locked position, a removable sheet metal ma azine having a ges successively 1nto the path of return movement of the bolt,

the said magazine having a seam at the rear thereof for olding the cartridges forward,

and a stop mounted independently of themsligazine and adapted to be engaged by the fo ower and moved upward into the path of return movement of the bolt after the last cartri e has been removed from the moved from the magazine, t e said stop thus serving to hold the breech bolt in its rearward position.

In testimony whereof I have hereunto set my hand this 10th day of March, 1928.

JONATHAN EDMUND BROWNING.

e .magazine, t e said stop being at the rear of f the ath of movement of the cartri es as glli ed by the said seam and the sai stop when in its up the breech bolt 1n its rearward osition.

, 30. In-a firearm of .theclass escribed, the

combination of a receiver having a'l dmally extending opening inthe bottom of portlonkthereof, a barrel and per position serving lto `hold barrel extension carried by the receiver and 'f movable upon recoil rearward relatively leasable v, means normally -llppn recoil to unlock the rearward inde endentl thereof, a spring for returning the` reech bo t to its normal locked position, a removable magazine normally p0- thereto, a rearward movable breech bolt,

locking thebreech Vbolt to the barrel extension means operative y breech bolt from the barrel extension and permit it to move 

